Fig. 5. Adsorption isotherms of Pb²⁺ on Fe₃O₄@DHAQ_GO nanocomposite at different temperatures. (Adsorbent dosage 100 mg L⁻¹; volume of solution 100 mL; pH 7; Pb²⁺ initial concentration range 1–10 mg L⁻¹). Points: experimental data at given temperature, lines: Sips model.